Current State of Forensic Science Improvement in the United States: Lessons from Wrongful Convictions

Advocates and researchers have made many recommendations for forensic science improvement in the United States. These proposals are often motivated by wrongful convictions related to false or misleading forensic evidence. In many cases, the connection between the proposals and the actual experience of wrongful convictions has not been well defined. Further, recommendations may not have been realizable given the structure of the criminal justice system in the United States and the practical realities of forensic science laboratories. Finally, limited attempts have been made to assess recommendations over time to determine the progress of forensic science improvement and elucidate continuing gaps. Reports from the Department of Justice, the National Academy of Sciences, and the President's Council of Advisors on Science and Technology are assessed to determine the extent to which their recommendations have been implemented, whether the recommendations align with the actual experience of wrongful convictions, and how the American forensic science community has implemented forensic science improvement. The most successful proposals reflect a broad movement toward quality assurance, improved standards, and organizational improvement in the forensic sciences. Less successful proposals are associated with calls for large federal investments, difficulties in community-wide implementation, or uncertain linkage to foundations in science and practice. Significant progress has been made in the standardization of reporting and testimony, assessment of the foundational reliability of the disciplines, and DNA mixture interpretation. Significant gaps remain to improve medicolegal death investigation, governance, and the implementation of standards. Improved allocation and use of resources will be required to meet continuing challenges in capacity building, training, and proficiency testing, although past experience indicates that both federal and non-federal funding will be required to address these issues. Continued improvement is needed to address the issues associated with wrongful convictions, although forensic science leaders have demonstrated the ability to prioritize improvement initiatives.

Polyethylene Degradation by a Rhodococcous Strain Isolated from Naturally Weathered Plastic Waste Enrichment

Polyethylene (PE) is the most widely produced synthetic polymer and the most abundant plastic waste worldwide due to its recalcitrance to biodegradation and low recycle rate. Microbial degradation of PE has been reported, but the underlying mechanisms are poorly understood. Here, we isolated a Rhodococcus strain A34 from 609 day enriched cultures derived from naturally weathered plastic waste and identified the potential key PE degradation enzymes. After 30 days incubation with A34, 1% weight loss was achieved. Decreased PE molecular weight, appearance of C-O and C═O on PE, palmitic acid in the culture supernatant, and pits on the PE surface were observed. Proteomics analysis identified multiple key PE oxidation and depolymerization enzymes including one multicopper oxidase, one lipase, six esterase, and a few lipid transporters. Network analysis of proteomics data demonstrated the close relationships between PE degradation and metabolisms of phenylacetate, amino acids, secondary metabolites, and tricarboxylic acid cycles. The metabolic roadmap generated here provides critical insights for optimization of plastic degradation condition and assembly of artificial microbial communities for efficient plastic degradation.

A long-period radio transient active for three decades

Several long-period radio transients have recently been discovered, with strongly polarized coherent radio pulses appearing on timescales between tens to thousands of seconds^1,2. In some cases, the radio pulses have been interpreted as coming from rotating neutron stars with extremely strong magnetic fields, known as magnetars; the origin of other, occasionally periodic and less-well-sampled radio transients is still debated³. Coherent periodic radio emission is usually explained by rotating dipolar magnetic fields and pair-production mechanisms, but such models do not easily predict radio emission from such slowly rotating neutron stars and maintain it for extended times. On the other hand, highly magnetic isolated white dwarfs would be expected to have long spin periodicities, but periodic coherent radio emission has not yet been directly detected from these sources. Here we report observations of a long-period (21 min) radio transient, which we have labelled GPM J1839-10. The pulses vary in brightness by two orders of magnitude, last between 30 and 300 s and have quasiperiodic substructure. The observations prompted a search of radio archives and we found that the source has been repeating since at least 1988. The archival data enabled constraint of the period derivative to <3.6 × 10^-13 s s^-1, which is at the very limit of any classical theoretical model that predicts dipolar radio emission from an isolated neutron star.

Target integration of an exogenous β-glucosidase enhances cellulose degradation and ethanol production in Clostridium cellulolyticum

The bacteria Clostridium cellulolyticum is a promising candidate for consolidated bioprocessing (CBP). However, genetic engineering is necessary to improve this organism's cellulose degradation and bioconversion efficiencies to meet standard industrial requirements. In this study, CRISPR-Cas9n was used to integrate an efficient β-glucosidase into the genome of C. cellulolyticum, disrupting lactate dehydrogenase (ldh) expression and reducing lactate production. The engineered strain showed a 7.4-fold increase in β-glucosidase activity, a 70% decrease in ldh expression, a 12% increase in cellulose degradation, and a 32% increase in ethanol production compared to wild type. Additionally, ldh was identified as a potential site for heterologous expression. These results demonstrate that simultaneous β-glucosidase integration and lactate dehydrogenase disruption is an effective strategy for increasing cellulose to ethanol bioconversion rates in C. cellulolyticum.

A radio transient with unusually slow periodic emission

The high-frequency radio sky is bursting with synchrotron transients from massive stellar explosions and accretion events, but the low-frequency radio sky has, so far, been quiet beyond the Galactic pulsar population and the long-term scintillation of active galactic nuclei. The low-frequency band, however, is sensitive to exotic coherent and polarized radio-emission processes, such as electron-cyclotron maser emission from flaring M dwarfs¹, stellar magnetospheric plasma interactions with exoplanets² and a population of steep-spectrum pulsars³, making Galactic-plane searches a prospect for blind-transient discovery. Here we report an analysis of archival low-frequency radio data that reveals a periodic, low-frequency radio transient. We find that the source pulses every 18.18 min, an unusual periodicity that has, to our knowledge, not been observed previously. The emission is highly linearly polarized, bright, persists for 30-60 s on each occurrence and is visible across a broad frequency range. At times, the pulses comprise short-duration (<0.5 s) bursts; at others, a smoother profile is observed. These profiles evolve on timescales of hours. By measuring the dispersion of the radio pulses with respect to frequency, we have localized the source to within our own Galaxy and suggest that it could be an ultra-long-period magnetar.

A patient with regressing atypical histiocytosis running a far from benign course

We describe a case of regressing atypical histiocytosis (RAH) which showed evidence of aggressive local disease and systemic involvement. Both the local response of this patient to low dose radiotherapy and the systemic response to combination chemotherapy were clinically complete and rapidly achieved.

Extradural metastases in a case of medulloblastoma

Extradural metastases in medulloblastoma appear to be rare. We describe a case associated with use of a lumbar drain and propose that in this situation, adjuvant chemotherapy and possibly extension of the radiotherapy field to include the entire sacral epidural fat-space to the lower border of S5, should be considered.

Hemodynamic mechanisms of emerging portal hypertension caused by schistosomiasis in the hamster

A hamster model of schistosomiasis has provided the first opportunity to sequentially examine the early phases of the development of portal hypertension in a natural model of chronic liver disease. Groups of hamsters were infected with 50 cercariae of Schistosoma mansoni and underwent hemodynamic evaluation at intervals of 5, 8, 12 and 20 wk after infection. A progressive rise in intrahepatic resistance (from 4.0 +/- 0.4 to 8.4 +/- 1.0 mm Hg min.ml-1.gm liver weight [p less than 0.01]) appeared to play a major role in the initial stages of evolving portal hypertension. A gradual decline in portal blood flow (from 2.1 +/- 0.3 to 1.3 +/- 0.1 ml.min-1.gm-1 liver weight [p less than 0.01]) was only partially compensated for by an increase in hepatic arterial flow. Accordingly, by week 20, total hepatic blood flow decreased 23%. Liver weight that increased markedly between 5 and 12 wk after infection, as a result of the acute accumulation of obstructing granulomas, stabilized between wk 12 and 20, while a gradual but progressive rise in hepatic collagen content was seen. Portal pressure increased 75% during the study period. Chronic examination of this natural model should help define the pathogenesis of the complications of portal hypertension and contribute to the basis for effective intervention in this disease process.

Resistance to reinfection in experimental murine schistosomiasis: role of porto-hepatic hemodynamics

Experiments were conducted to evaluate critically, and independently of the immune system, the possible role of hemodynamic mechanisms in resistance to schistosomal reinfection. The effects of a challenge schistosomal infection were compared in groups of mice which were either previously infected with schistosomiasis, vaccinated with irradiated cercariae, or underwent partial portal vein ligation for the induction of portal hypertension and porto-systemic shunting. Following infection with 60 cercariae, the appearance of portal hypertension preceded by approximately 2 weeks the development of porto-systemic shunting, which reached maximal values 11 weeks postinfection. Such a primary infection conferred on C3H mice an estimated 90% protection to a 2nd infection, measured by the reduction of worm burden. Worm burdens were also reduced in vaccinated and ligated animals as compared to normal controls. The protection amounted to 30% and 56%, respectively, in the C3H strain and 63% and 75-85%, respectively, in the C57Bl/6 strain. Reduction in worm burden in the ligated animals is believed to be due to the extrahepatic porto-systemic vascular shunts. Hemodynamic as well as immunological factors may account for the resistance to reinfection observed in chronic murine schistosomiasis.

Centroid position measurements and subpixel sensitivity variations with the MAMA detector

Initial measurements of the position sensitivity of a visible-light multi-anode microchannel array (MAMA) detector show that centroid calculations for image spots are accurate to better than 0.04 pixels even with sources that are essentially delta functions at the photocathode. Subpixel sensitivity variations of 10-15% are typically found for pixels in the array. Variations as large as 30% are possible in the worst conditions. These variations limit the photometric accuracy of the detector when very small scale features are observed. The photometric accuracy and the position sensitivity of the detector appear to be limited by cross-coupling effects within the anode array. Initial measurements with more recent designs of the detector show that most or all of this cross-coupling has been eliminated. We will report on the position sensitivity of the newer detectors when they become available for testing.

Somatostatin in portal hypertension

The effect of somatostatin on portal pressure is mediated by splanchnic arterial vasoconstriction which induces a reduction in portal blood flow and pressure. One of the most important characteristics of somatostatin is that its splanchnic effect is not accompanied by major systemic hemodynamic effects. Somatostatin has been used in several controlled trials to test its potential in controlling acute variceal bleeding. The results remain controversial. Different findings in existing clinical trials may derive in part from distinct protocols for somatostatin administration. Published trials suggest that somatostatin may be as effective as vasopressin in the acute management of variceal bleeding. However, since the efficacy of vasopressin has been questioned, a comparison of two potentially ineffective drugs cannot establish definitively the efficacy of somatostatin in controlling variceal bleeding. The most significant finding of the two published studies has been the lower incidence of minor and major complications with somatostatin when compared to vasopressin. Newer trials in progress may shed new light into the potential use of somatostatin for the treatment of variceal bleeding.

ICI 169,369 selectively blocks 5-hydroxytryptamine2 receptors and lowers portal pressure in portal hypertensive rats

The contractile effects of 5-hydroxytryptamine on isolated portal veins and superior mesenteric veins of portal hypertensive rats (portal vein constricted) were antagonized competitively by ICI 169,369. The equilibrium dissociation constant of 1-3 nM for ICI 169,369, estimated in the veins, agrees with affinity estimates for arterial 5-hydroxytryptamine2 receptors. The receptors of portal veins of sham-operated rats had the same affinity for ICI 169,369 as the receptors of portal hypertensive rats. The systemic administration of ICI 169,369 to portal hypertensive rats decreased portal pressure from 13.0 +/- 0.4 to 11.3 +/- 0.5 mmHg (p less than 0.01) but did not affect arterial pressure. ICI 169,369 induced nonsignificant changes in both portal venous inflow and portocollateral resistance, as estimated by the radioactive microsphere technique. It is estimated that the combined changes in portal flow and resistance could explain the decrease in portal pressure. The results are consistent with an involvement of 5-hydroxytryptamine, acting through 5-hydroxytryptamine2 receptors, in prehepatic portal hypertension.

Imaging extreme ultraviolet spectrometer employing a single toroidal diffraction grating: the initial evaluation

A high-efficiency extreme ultraviolet (EUV) imaging spectrometer has been constructed and tested. The spectrometer employs a concave toroidal grating illuminated at normal incidence in a Rowland circle mounting and has only one reflecting surface. The toroidal grating has been fabricated by a new technique employing an elastically deformable submaster grating which is replicated in a spherical form and then mechanically distorted to produce the desired aspect ratio of the toroidal surface for stigmatic imaging over the selected wavelength range. The fixed toroidal grating used in the spectrometer is then replicated from this surface. Photographic tests and initial photoelectric tests with a 2-D pulse-counting detector system have verified the image quality of the toroidal grating at wavelengths near 600 A. The results of these initial tests are described in detail, and the basic designs of two instruments which could employ the imaging spectrometer for astrophysical investigations in space are briefly described, namely, a high-resolution EUV spectroheliometer for studies of the solar chromosphere, transition region, and corona and an EUV spectroscopic telescope for studies of nonsolar objects.

Opportunistic strongyloidiasis in renal transplant recipients

Eight patients with severe strongyloidiasis complicating renal transplantation are reported. Twenty-one additional cases from the English-language literature are reviewed. In this setting, systemic strongyloidiasis is an often baffling illness involving multiple organ systems that is frequently complicated by serious bacterial infection. Bacteremia, meningitis, urinary tract infection, and pneumonia resulting from enteric organisms are common. In order to make the diagnosis, larvae must be sought by direct microscopy of stool, upper intestinal fluid, sputum, urine, or biopsy specimens. Treatment with oral thiabendazole in prolonged or repeated courses is recommended. Effective parenteral therapy is not available. Following treatment, previously parasitized patients must be tested at regular intervals to detect therapeutic failure or reinfection. Screening of patients awaiting renal transplantation for chronic intestinal strongyloidiasis is suggested. Improvement of the observed 52% mortality will depend upon heightened awareness by physicians caring for renal transplant candidates, and upon improved therapeutic regimens.

Evidence that the antitumor agent hydroxyurea enters mammalian cells by a diffusion mechanism

Very little information is available about the process responsible for the uptake of the antitumor agent hydroxyurea by mammalian cells. Therefore we have investigated the transport of hydroxy[14C]-urea into Chinese hamster ovary cells. Using a convenient and reproducible 2 min. assay we found that hydroxyurea was taken up in a linear nonsaturable fashion between 0.01 mM and 100 mM drug. The Km for hydroxyurea uptake was essentially zero and the Vmax appeared to be infinite, suggesting a diffusion mechanism. The observation that intracellular drug concentrations were consistently less than medium concentrations indicated that uptake was not an active process. Experiments performed with the metabolic inhibitor sodium azide, and investigations at different assay temperatures also gave results consistent with a mechanism of drug diffusion. In total, the results obtained in this study are in agreement with the proposal that hydroxyurea enters the cell primarily by a process of diffusion. These observations provide a more complete understanding of the mode of action of this widely used drug.

Incomplete baroreceptor responses in newborn infants

Previous studies of the baroreceptor response to a 45 degree head-up tilt in preterm and mature infants during the first 3 days of life failed to demonstrate a significant tachycardia while eliciting a 25% reduction in limb blood flow. In order to determine if maturity or respiratory distress affected the presence of tachycardia after tilting, 34 infants between 28 and 40 weeks gestation, including 15 infants with RDS, were studied serially during their hospitalization in a neonatal intensive care unit. In the first 5 seconds after a rapid (1-second) tilt to 45 degrees, individual infants responded with changes in heart rate (HR) ranging from a fall of 8 beats/min to an increase of 13 beats/min. Individual responses were not predictable on the basis of maturity at birth, age after birth, or presence of clinical respiratory distress. The group as a whole demonstrated a statistically significant increase of 2 +/- 4 beats/min in the first 5 seconds immediately after tilting. This may be compared to a coefficient of variation of +/- 4-5% in the resting HR of the same group of infants. Because of the unpredictability of individual responses and the small magnitude of the response for the group as a whole, it can be concluded that the HR component of the baroreceptor response is poorly developed during the neonatal period.

Factitious renal stone as a sign of internal conflict about sexual intercourse in an adolescent

Conflicts about the onset of sexual intercourse have been reported to cause a variety of symptoms. A 16-year-old black female claimed to have passed a stone in her urine. Investigation of her complaints caused some doubt that an organic cause was involved. Social history showed that she had recently begun to have sexual intercourse despite a religious belief that intercourse before marriage was wrong. After an extensive medical work-up, she was discharged with instructions to bring in another stone if passed. A stone subsequently presented by the patient proved to be a piece of lead shot. Those caring for adolescents need to be aware that conflicts about sexual intercourse may present in a number of ways, including urinary-tract complaints.

Detection of Singly Ionized Oxygen Around Jupiter

Forbidden emission from singly ionized oxygen at wavelengths of 3726 and 3729 angstroms has been detected in the inner Jovian magnetosphere. The emission is present between approximately 4 and approximately 7 to 8 Jovian radii from the planet and appears concentrated in the magnetic equator. The line intensity ratio indicates the same plasma characteristics as those derived from observations of forbidden sulfur emission.